Base-Sensitive Polymers as Imaging Materials:  Radiation-Induced β-Elimination To Yield Poly(4-hydroxystyrene)

A novel family of functionalized polystyrenes that are susceptible to base-catalyzed β-elimination is reported. A study of the thermal behaviors of poly[(((((2-cyano-1,1-dimethylethyl)oxy)carbonyl)oxy)styrene], poly[(((2-cyanoethoxy)carbonyl)oxy)styrene], and poly[((((2-methylsulfonyl)ethoxy)carbonyl)oxy)styrene] confirms that they undergo facile and quantitative elimination of their side chain groups in a process that is susceptible to base catalysis. Imaging of these polymer systems was accomplished using the novel ,4,4'-[bis[[(2-nitrobenzyl)oxy]carbonyl]trimethylene]dipiperidine as an amine photogenerator. Copolymerization of ((((2-cyano-1,1-dimethylethyl)oxy)carbonyl)oxy)styrene and ((t-butoxycarbonyl)oxy)styrene followed by selective deprotection of the t-BOC protecting groups with acid enabled the synthesis of a base-sensitive copolymer containing free phenol units with enhanced thin-film properties.